Article ID Journal Published Year Pages File Type
1599906 Intermetallics 2015 5 Pages PDF
Abstract

•5-2-2 type main phase (monoclinic), 5-4 and 5-3 type secondary phases were obtained.•A field induced magnetic transition was exhibited at 143 K.•|ΔSMmax| of the alloy is 22.4 J/kg K when applying field from 0 to 5 T.•The refrigeration capacity of the alloy is 261 J/kg in a field change of 5 T.•The average hysteresis loss of the alloy is 30 J/kg for a field change of 5 T.

Tb4Gd1Si2.035Ge1.935Mn0.03 alloy was prepared by arc melting followed by annealing at 1193 K for 168 h. Structural characterizations reveal that monoclinic (Tb, Gd)5Si2Ge2-type phase, secondary phase with orthorhombic 5-4 type structure and hexagonal 5-3 type structure coexist in the alloy. The paramagnetic Curie temperature (θp) is 120 K, indicating that the dominant exchange interaction is ferromagnetic or ferrimagnetic. That the thermal hysteresis of 13 K between heating and cooling and the negative slopes of Arrott plots derived from M–H curves between 116 K and 170 K confirm a typical first-order magnetic transition from ferromagnetism to paramagnetism occurs. The maximum magnetic entropy changes of the Tb4Gd1Si2.05Ge1.95Mn0.03 alloy for magnetic field changes of 0–1 T, 0–2 T, 0–3 T, 0–4 T and 0–5 T are about 3.3, 8.6, 14.0, 18.9 and 22.4 J/kg K, respectively. And the effective refrigeration capacity (RCeff) value is 231 J/kg with a subtracted magnetic hysteresis loss of 30 J/kg for a magnetic field change from 0 to 5 T. Large −ΔSM and RCeff suggest that Tb4Gd1Si2.035Ge1.935Mn0.03 alloy is an attractive potential magnetocaloric material working in the vicinity of 143 K.

Related Topics
Physical Sciences and Engineering Materials Science Metals and Alloys
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